Ophthalmic surgery saves and improves the vision of tens of thousands of patients every year. However, given the sensitivity of vision to even small changes in the eye and the minute and delicate nature of many eye structures, ophthalmic surgery is difficult to perform and the reduction of even minor or uncommon surgical errors or modest improvements in accuracy of surgical techniques can make an enormous difference in the patient's vision after the surgery.
Ophthalmic surgery is surgery performed on the eye or any part of the eye. Ophthalmic surgery is regularly performed to repair retinal defects, repair eye muscles, remove cataracts or cancer, or to restore or improve vision. Certain surgical procedures, for example repairing a retinal detachment, may require a vitrectomy before subsequent procedures may be performed. A vitrectomy is a surgical procedure in which the vitreous is removed from the eye. The vitreous is a clear gel-like substance that holds the retina in place. In certain surgical procedures, the surgeon may need to remove the vitreous to allow access to the retina or other internal structures. In such procedures, the vitreous may be cut and aspirated out of the eye in a procedure called a vitrectomy.
In a vitrectomy, the surgeon inserts small surgical instruments into the eye. Such instruments often include a cutting instrument, a general light source, and an infusion cannula. The cutting instrument may be a vitreous visualization device (VVD), which includes a vitreous cutter and an aspirator to remove portions of the vitreous that have been cut. The VVD may be connected to an optical fiber. The optical fiber propagates an intense illumination beam, generated by an intense light source, called the VVD light source, which is often a laser. This light source provides direct illumination to the vitreous cutter, so that the cutter may be precisely operated in the clear vitreous. The general light source provides basic illumination in the eye that is a significantly lower intensity in comparison to the illumination beam generated by the VVD light source. The infusion cannula is a thin tube that is used to administer water, oil, or a gas to the eye, to replace the vitreous aspirated. This infusion allows the eye to maintain its volume during the procedure so that it does not collapse or become deformed. When performing a vitrectomy, it is important to monitor the patient's risk of phototoxicity caused by light sources used in surgery.